The present invention relates to a multi-size convertible catheter capable of having its outer diameter altered by removing superimposed, peelable layers. The multi-size catheter is particularly useful in conjunction with an endoscope for accessing the alimentary canal within the human anatomy and methods of using such a catheter. The peelable layers may be selectively removed from the multi-size catheter in order to obtain an outer diameter for the catheter that is less than, but approximate to, the inner diameter of the working channel of the endoscope.
Endoscopic procedures for treating abnormal pathologies within the alimentary canal system and biliary tree (including the biliary, hepatic, and pancreatic ducts) are increasing in number. The endoscope provides access to the general area of a desired duct using direct visualization. However, the duct itself must be navigated using a catheter in conjunction with fluoroscopy and guidewires.
Catheters are known for treatment of targeted anatomical regions. Known methods and devices for using biliary catheters for accessing the biliary tree for performing catheter procedures are disclosed in Weaver et al., U.S. Pat. No. 5,397,302 and Karpiel, U.S. Pat. No. 5,320,602, the disclosures of which are herein incorporated by reference.
In general, for treatment of an abnormal pathology within a patient""s biliary tree, an endoscope is first introduced into the mouth of the patient. The endoscope includes a proximal end and a distal end, and has a lumen extending longitudinally between the proximal and distal ends. The endoscope is guided through the patient""s alimentary tract or canal until an opening at the distal end of the endoscope is proximate the area to receive treatment. At this point, the endoscope allows other components, such as a catheter, to access the targeted area.
For visualization or treatment within the biliary tree, the distal end of the endoscope is positioned proximate the papilla of vater leading to the common bile duct and the pancreatic duct. A catheter is guided through the lumen of the endoscope until a distal tip of the catheter emerges from the opening at the distal end of the endoscope.
The catheter may be used for accessing the biliary tree. The distal end of the catheter is guided through the orifice to the papilla of vater (located between the sphincter of oddi) leading to the common bile duct and the pancreatic duct. A guidewire may be used in conjunction with the catheter to facilitate accessing a desired location within the biliary tree. The guidewire is inserted in an opening at a proximal end of the catheter and guided through the catheter until it emerges from the distal end of the catheter.
If visualization of the common bile duct is desired, the guidewire is guided into the common bile duct. The catheter is advanced over the guidewire, as previously described, until the distal end of the catheter is positioned in the common bile duct at the desired location. The catheter is now in position for delivery of contrast media for fluoroscopic visualization of anatomical detail within the common bile duct. Once the guidewire is in place relative to the targeted area, it is highly desirable to maintain that position of the guidewire during subsequent catheter procedures, including catheter exchange procedures.
Present biliary endoscopic procedures include the use of multi-lumen catheters for endoscopic retrograde cholangiopancreatography, endoscopic retrograde sphincterotomy, the use of balloon catheters having retrieval balloons, and other therapeutic and diagnostic procedures. As described in general above, these present biliary endoscopic procedures are performed using guidewire techniques. The present devices utilized in these procedures are at least 180 cm long since they pass through the endoscope, which is commonly at least 150 cm long. Therefore, when using a standard catheter having a guidewire lumen extending the full length of the catheter, guidewires used during these procedures must be at least 400 cm in length to accommodate the exchanging of different devices while maintaining access and position within the biliary tree. The exchange of devices over a 400 cm guidewire is both time consuming and cumbersome.
Due to the length of the guidewire, physicians require at least two assistants in the room to perform the biliary endoscopic procedure. Typically, one assistant is responsible for the patient and device-related concerns, while the other assistant is responsible for the guidewire. The additional hands required due to the length of the guidewire results in a relatively more time consuming and costly procedure.
It is desirable to have an exchange catheter suitable for use within the alimentary canal for accessing targeted anatomical regions, such as the biliary tree, having features which facilitate rapid exchange and allow an exchange procedure to be performed by a single operator. It is desirable to have a biliary exchange catheter which may be used in connection with a shorter guidewire, and requires less personnel for performing biliary procedures. It is desirable to have a biliary exchange catheter which limits the amount of guidewire over which the catheter must travel.
It is also desirable to have a biliary rapid exchange catheter which may be convertible for use between conventional guidewire techniques and rapid exchange guidewire techniques. It is desirable to have a biliary rapid exchange catheter which is easily removable from the guidewire, and adaptable for use with most catheter systems used within the alimentary canal.
The present invention relates to a multi-size convertible catheter for use in biliary endoscopic procedures. In particular, the present invention overcomes many of the disadvantages of the prior art by providing a catheter that incorporates the structural features of an endoscope sheath into a single medical device. Specifically, in preferred embodiments, the multi-size catheter comprises a plurality of peelable layers forming the outer diameter of the catheter. The peelable layers may be individually removed allowing the outer diameter of the catheter to be varied.
A preferred embodiment for the multi-size convertible catheter includes a catheter shaft having a proximal end and a distal end. The multi-size catheter additionally includes a guidewire lumen carried by the shaft extending from a location proximal of the distal end of the shaft to a location proximate the distal end of the shaft. Means are provided for accessing the guidewire lumen from a location exterior to the catheter shaft, located a substantial distance distal of the proximal end of the shaft. The means for accessing the guidewire lumen may include an open channel extending through a wall of the catheter shaft. The multi-size catheter further includes at least one, but preferably a plurality of peelable layers co-axially disposed over the catheter shaft. Means are provided for removing individual peelable layers from the exterior of the multi-size catheter. The means for removing the peelable layer preferably includes a perforated line within the peelable layer. The perforated line may be slit, whereby the peelable layer may be separated from the catheter by extracting the peelable layer from the slit.
In one embodiment, the multi-size convertible catheter has an outer diameter sufficient for placement within the largest endoscope working channels. The tolerance between the outer diameter of the catheter and the working channel is smaller than the diameter of a guidewire. Guidewire movement, therefore, is constrained to within the guidewire channel of the catheter only. The guidewire is effectively stopped from slipping out of guidewire channel thereby eliminating the potential for the guidewire to become pinched and restrict desired movements of both the guidewire and the catheter.
In another embodiment, the multi-size convertible catheter is adapted for endoscopes of varying working channel diameters. The multi-size catheter comprises an outer diameter defined by a plurality of superimposed co-axially disposed peelable layers. Before positioning the multi-size catheter within the working channel of an endoscope, the peelable layers may be selectively removed in order to obtain an outer diameter for the catheter that is less than, but approximate to, the inner diameter of the working channel of the endoscope. A correct fit between the catheter and the working channel of an endoscope reduces the potential for the guidewire to slip out of the guidewire channel and become pinched.